1. Field of the Invention
The present invention relates to film image reading apparatus.
2. Description of Related Art
Film scanners are apparatus that read (i.e., image or scan) film images from film photographed by conventional cameras. Film scanners read the images from negative-type film and from reversal-type film in order to acquire an electronic version of the images, which can then be input, e.g., to a personal computer, and the like. One inexpensive, general configuration provides an optical system that is fixed and a conveyor device that conveys the film past the optical system.
One example of a film that can be used in a film scanner is disclosed in Japanese Laid-Open Patent Application No. 5-75922. As shown in FIG. 4, this film 55 includes a magnetic recording layer.
The film 55 can be housed inside a film cartridge 51, having one end fixed to a spool 52. Perforations 53 and a magnetic recording section 54 are provided on the film 55, one per photographic frame. A frame number 0 (not illustrated), which is an area on which an image is not photographed, precedes the first photographic frame on the film 55. A perforation and a magnetic recording section are also provided for frame number 0.
Film cartridge 51 also includes an optically readable label that displays information indicating, for example, whether or not film 55 is developed and information indicating the type of film 55. The information indicating the type of film includes, for example, information indicating whether the film is negative or positive, information indicating whether the film is black-and-white or color, and information indicating the manufacturer's name and the type (i.e., model) number of the film. The optically readable label can be, e.g., a bar code.
One example of a feeding device for film housed in a cartridge is disclosed in Japanese Laid-Open Patent Application No. 7-219029. In this device, the film is sandwiched by a pinch roller and capstan roller, which are located between the position of a fork and the position of a take-up spool. The fork delivers the film from the cartridge by engaging with the film take-up shaft of the cartridge and rotating the take-up shaft. The take-up spool takes-up the film delivered from the cartridge and is located on the opposite side of the reading position relative to the fork. Driving of the spool, the rollers and the fork is controlled in a delayed fashion so as to maintain a relationship therebetween. First the driving of the take-up spool is controlled, then the capstan roller, and then the delivery fork. A clutch also is positioned on the take-up spool so as to absorb any difference of velocity with the capstan roller.
In these devices, the precision of the feeding of the film at the reading position is determined by controlling the rotation speed of the pinch roller and the capstan roller. The rotation speed of the pinch roller and the capstan roller depends on the speed at which the film is taken-up by the take-up spool. However, the rotational velocity of the effective outer perimeter of the take-up spool (i.e., the circumference of the take-up spool and surrounding film) becomes faster as the amount of film taken-up increases. In order to absorb this change of velocity, velocity control and a clutch mechanism as mentioned above were necessary, and the totality of the take-up section became complex and high-priced.